You and Castile, who had saved Dean from hell, were interrupting a hunt the Winchesters were on. They needed to catch a witch, soon, before another seal broke.

Sam entered the room first, gun drawn before Dean stopped him. “Woah, hey, angels.” Dean said. Sam’s face dropped, he was excited but trying to hide it. He turned to Castiel first. Who was immediately rude to him.

You interrupt Castiel, with a little more tact, you’ve been on earth longer than him.